Prestressed structural unit



.R. L. DAVISON ET AL 2.178.097

' PRES'IRE ISSED STRUCTURAL UNIT Filed Dec 14, 1937 L xlmmg INVENTORS ROBERT L. DAVISON YREDERI K 0.A EREGG %7 M T RNEY if u Patented Oct. 31, 1939 W I! r Robert L. Da son, New York, N. Y., and Frederick 0. Anderegg, Newark, Ohio, assignors to John. B. Pierce Foundation, New York, N. Y., a corporation of New York Application December 14, 19.37, Serial No. 179,654

7 Claims. (01. 72-68) Among the principal objects of the invention tageously angle-irons associated together in such, 5 are to provide: manner that their open-angles are outwardly 1) A structural unit appropriately prestressed directed and, further, preferably such that comunder both tension and compression. ponent leg members are each associated in a (2 A structural unit of considerable strength respective set of leg members-see Ha, I 2a, l3a, and yet of light weight. I 4a and II b, l2b, [3b, I 4b-whlch lie in parallel 10 (3) A structural unit comprising cementitious planes, the vertices of the angle-irons being dimaterial prestressed under the compression of a rected inwardly of the framework. reinforcing framework, which is prestressed un- The two frame lateral members, II and I2, are der tension. rigidily secured to respective ends of longitudinal (4) A structural unit pie-fabricated for simframe members I3, as by means of tongues Ho 15 plicity and for positivity of securement to other and I20, respectively, such tongues being formed structure in a building construction. by cutting the respective angle-irons l l and I 2 It is preferred to utilize the material Micro at their ends along the vertices thereof and by porite disclosed in United States Pat. No. bending the freed end portion of leg members 1,932,971, granted to Hiittemann and Czernin, as Nb and I 222, respectively, outwardly. The 80 the composition filler material for the structural tongue so formed may be welded to the respecunit. Such material is of light weight, has an tive ends of leg B1) of longitudinal angle-iron l3. extremely high porosity, and is frangible under The longitudinal member, i. e. angle-iron, l4 ordinary handling conditions unless enclosed by is adjustably mounted, with respect to the other a reinforcing framework. It has been found that members of the framework, so that it may be u Microporite, when properly prestressed, is suftensioned between the free ends of lateral memficiently strong for a great number of building bers II and I2, of the framework. In the illuspurposes, and affords structures of unusual lighttrated embodiment, to accomplish the desired ness and insulating qualities. tensioning of longitudinal member l4, such mem- Pursuant to the present invention a reinforcher is made shorter than the gap between free ing framework is provided, preferably rectanends of frame lateral members H and I2, into gular in shape, and having one side thereof adwhich it fits, and is connected at its ends with justably mounted in the framework proper by such free ends of the frame lateral members by suitable tensioning means. Upon incorporating suitable tensioning means. As illustrated, see into such framework cementitious composition especially Fig. 4, the tensioning means may conmaterial, such as Microporite, the tensioning veniently take the form of machine screws 15 and means may be adjusted to prestress the frame I 6, extending through unthreaded holes in the member under tension, thereby placing the comfree end of leg members lib and I'Zb, respectiveposition filler material under compression. ly, for threaded engagement with studs l1 and I8,

In the drawing, ,respectively, secured to leg member Nb of frame 40 Fig. 1, represents a plan view of one embodilongitudinalmember l4. ment of reinforcing framework before the com- 'I'heframework is desirably provided with lonposition filler material is incorporated therein. gitudinal reinforcing rods, as at l9, which ex- Fig. 2 represents a condensed vertical section tend between frame lateral members II and I2, taken on the line 22, Fig. 1, illustrating the their threaded ends being received by unthreadstructural unit complete with composition filler ed holes'in leg members lib and I222, respectivematerial, and as extending between vertical uply, and being secured in place by nuts, as at 20, rights in a building construction. 2|, screwed on the stated threaded ends. The

Fig. 3 represents a condensed vertical section framework is, further, desirably provided with retaken on the line 33, Fig. 1, of the complete unit inforcing rods, as at 22, extending between the as illustrated in Fig. 2. angle-iron leg members I31) and Nb of longi- Fig. 4 represents an enlarged detail view of tudinal frame,members l3 and I4, transverse to the lower left-hand corner portion of Fig. 1. the longitudinal reinforcing rods l9, their Referring to the drawing: threaded ends being received by unthreaded holes I The numeral l0 indicates a peripheral reinin the stated leg members, and the rods being This invention relates to prestressed structural units and applies particularly to panel units formed from cementitious composition material enclosed by a reinforcing frame.

forcing framework, rectangular in configuration, and comprised of the two lateral members H and I2, and the two longitudinal members l3 and M. The respective frame members are advanheld in place by nuts, as at 23, 24, the threaded rod ends.

As before stated, it is preferred to employ the light weight, highly porous material Microporite as cementitious composition filler for attaining the desired slab formation of the structural unit; In the present embodiment, see especially Figs. 2 and 3, the structural unit has its reinforcing framework I filled with composition filler material 26 as illustrated, i. e. such that a portion of the material, see 261: extends backwardly from the frame to provide a slab face thereat, portions of such material, see 26b and 280, extending over and covering the outer surfaces of leg members IIb and I2b for concealing the projecting ends of rods 22. A reinforcing wire mesh 21 may be incorporated adjacent the slab surfaces, as illustrated. t

' Part of the cementitious filler material 26 preferably extends forwardly of the planes of leg screwed on members Ila, I2a, I3a and Ila to provide a slab face portion 26d substantially coextensive with the outermost boundary of the framework.

To afford joinder of the completed structural unit withother structure in a building construction, as indicated at 28, Fig. 2,, holes, as at 29, Fig. 1, may be drilled at appropriately spaced intervals along the frame leg members IIa, IZa, "a and Ila for the reception of suitable securing elements, such as the machine screws 30. The latter are positioned prior to the filling of the framework with the composition filler material 26, thus being incorporated, upon filling of the framework, as an integral part of the resulting structural unit.

The slab face portion 26d of the structural unit is advantageously covered by a sheet of weather resistant composition material 28, such as Morbelli" cement sheet disclosed in U. S. Patent No. 2,084,354, issued June 22, 1937, to Giovanni Morbelli, as by bonding to the surface thereof. Such weather resistant sheet adapts slab face portion 26d for exposure to exterior weather conditions when the structural unit is utilized as a primary structural material in building construction.

As illustrated in Fig. 3, the slab face portion 26d preferably stops short of the outer longitudinal edge of leg member I30. of longitudinal frame member I3, see 3I, to facilitate overlapping joinder, horizontally, of adjacentunits, and, also for this purpose and for the attainment of planar continuity of exterior wall surface, longitudinal llrame member I 3 s preferably set back with respect to longitudinal frame member I4 such that the tongue formation, see 32, Fig. 3, of one structural unit may be coordinately received by the groove formation, see 3|, Fig. 3, of an adjacent similar" structural unit.

After filling of the framework I0, as above de-' scribed, the structural unit may be prestressed by screwing machine screws I5 and I8 in their respective appropriate directions. In such manner, longitudinal frame members I 3 and Il will be stressed under tension while the composition filler mate'rtal 26 will be stressed under compression, resulting in a strong yet light-weight structural unit prestressed for use as a primary structural element in building construction.

Whereas this invention has been illustrated and described with respect to a specific preferred embodiment thereof, it is to be distinctly understood that many changes may be made without departing from the spirit of the invention as set forth herein and in the claims that here follow.

We claim:

1. A structural unit comprising a substantially rectangular peripheral framework having one of its component frame side members secured in a gap, formed between two mutually opposite frame side members, by means of tensioning devices operative' between said two mutually opposite frame side members and said one component frame side member, and composition filler material form-' ing a slab within the framework, said framework being adapted .to place and maintain said slab under compression.

' 2. A structural unit comprising a peripheral framework-having a gap therein, a component frame member slightly shorter than the length of the gap and adjustably positioned therein by tensioning means cooperating with the portions of said framework which define the gap, and composition filler'material forming a slab" within the framework, said framework being adapted to place and maintain said slab under compression.

3. A structural unit as recited in claim 2 wherein the tensioning means are threaded elements, each of which elements is threadedly received by an end portion of said component frame member and the adjacent portion of said framework which defines the gap.

4. A structural panel unit comprising a substantially rectangular peripheral framework formed of angle-irons whose respective vertices are directed inwardly of the framework, the respective leg members of each lying in a plane substantially parallel to the planes in which similar respective leg members of the others lie, and one set of leg members lying in a common plane with the exception of one of the component leg members of the set which is displaced from said common plane by a distance approximately equal to the thickness of the similar le of the frame member lying opposite thereto, and a panel slab of composition material enclosed by said peripheral framework.

5. A prestressed structural panel unit comprising a substantially rectangular peripheral framework formed of angle-irons whose respective vertices are directed inwardly of the framework, the respective leg members of each lying in a plane substantially parallel to the planes in which similar respective leg members of the others lie, and one set of leg members lying in a'common plane with the exception of one of" the longitudinal component leg members of the set which is displaced from said common plane by a distance approximately equal to the thickness of the similar leg of the frame member lying opposite thereto, a panel slab of composition material enclosed by said peripheral framework, and adJustable tensioning means securing one of the longitudinal frame members to the respective end frame members whereby said one longitudinal frame member is maintained under tension and said panel slab is maintained under compression.

, 6. In a structural unit embodying a peripheral framework and a slab of composition material enclosed withinthe peripheral framework, a component frameelement secured in said framework, and adjustable means securing respective end portions of said component frame element to respective free end portions of said framework, said adjustable means being so constructed and arranged that adjustment thereof places the said framework in tension and the said slab of composition material in compression.

portions or said framework, said adjustable means being so constructed and arranged that adjustment thereof places the said framework in tension and the said slab of composition material in compression.

ROBERT L. DAVISON. FREDERICK O. ANDERIGG. 

